This invention relates to a device to promote and facilitate the preliminary biological reduction of organic material in sewage and in waste water. In particular, this invention involves a device and method to reduce the grease and other organic materials which normally collects and deposits within waste water/sewage collection systems and/or the pretreatment of sewage within municipal sewage systems.
With increasing population concentration in most suburban and urban areas, it is necessary to collect the sewage from the individual residental, commercial and business sewage outflow and process it at a central location. At the treatment plant the sewage is treated to various stages allowing the resulting product to pass back into the ecological system. If left unchecked certain types of sewage outflow are too high in organic matter, such as grease such that the organic matter will clog the collection system at one or more of the critical points or will reach the primary sewage treatment plant and be essentially so indigestible by the ubiquitous bacteria present that it must be skimmed off and discarded in bulk after collection. With increases in population, present sewage treatment facilities are unable to process the increased volume of organic matter in the flow without significant capital investment in new equipment. Along the sewage transport lines to the treatment plant pumping stations are frequently located to transport the sewage to a higher elevation. These wet well locations serve as a collection point for grease and other organic matter that is not decomposed within the water flow. It is a common necessity to clean out the wet wells at pumping stations or other junction points in the system where floating grease and organic matter collects, hardens and remains there until it is removed by a pump to a truck. Lines with low flow rates, bends, and changes in elevation are also prone to build up organic deposits. Most states and municipalities have placed limitations on the quantities of oils and greases which may be introduced into the municipal sewage collection system. Most businesses and industrial companies generating grease in quanity are required to install a grease trap on the premises to collect the grease and prevent the bulk of it from entering the collection system. The grease collects in the trap until it is removed by hand or with a pump and truck.
Recently, an answer to the continuous removal and trucking away of the grease has been offered in the form of bacterial augmentation to maximize the effectiveness of organic decomposition. A bacterial supplement of highly-cultured strains of bacteria with an exceptionally high capacity for specific organic reduction are charged to the sewage system. These bacterial strains are designed to reduce the grease and convert it to lower molecular weight compounds which will not accumulate within the downstream sewage collection system. These bacteria operate almost exclusively in the water phase and their cultures grow at the grease/water interface on the sides and the bottom of the tank or trap in which they are placed. Those bacteria in the water phase are constantly washed out and passed down stream. Some of the bacteria are replenished by cultures that grow on the surface area of the walls of the trap. Apparently most are replenished by what grow at the grease to water interface. In addition, alien bacteria which compete with the supplemental bacteria constantly enter the system with fresh sewage. As a result, the highly cultured bacteria must be added frequently, as often as daily. When the source is generating a substantial amount of grease in areas of low detention time, the vast majority of the bacteria pass downstream and out into the transport system of the municipal sewer line. Many of these locations where grease collects are essentially anaerobic in nature. Anaerobic conditions slow the activity of common bacterial cultures.
Bacteria promoting devices are described in the following U.S. Pat. No. 2,051,727 to M. Levine et al, U.S. Pat. No. 2,183,657 to A.A. Page, U.S. Pat. No. 2,602,651 to M.R. Cannon, 3,293,174 to C.F. Robjohns, U.S. Pat. No. 4,005,010 to Lunt, U.S. Pat. No. 4,165,281 to Kuriyama et al, and U.S. Pat. No. 4,333,893 to Clyde. None of these devices satisfy the needs described above and do not attain the objects listed herein below.